Liquid filled magnetic compass



Dec. 25, 1956 L.. KADLEc LIQUID FILLED MAGNETIC coMPAss Filed May 4,1954 INVENTOR n0/.smv /wzfc fw/5d@ ATTORNEY;

United States Patent() LIQUID FILLED MAGNETIC COMPAS Ladislav Kadlec,Lansdale, Pa., assignor to American Machine and Metals, Inc., New York,N. Y., a corporation of Delaware Application May 4, 1954, Serial No.427,636 1 Claim. (Cl. 33-223) that parts must be compact yet accessobtainable for y servicing.

One of the objects of the invention is to provide an improved compassarrangement having the desired sensitivity and yet being substantiallyunaffected by shock or vibration.

Another object of the invention is to provide an improved compassassembly arranged so that access can be obtained with ease to thevarious parts.

A still further object is to provide an improved means for mounting thefront transparent panel or glass.

In one aspect of the invention, the compass has a bowl or chamber forreceiving the liquid, the bowl having a yieldable support therein uponwhich is mounted the floating card holding the magnets and which bearsthe conventional indicia. An opening is located in the front of thebowl, said opening being closed by a transparent plate or panel throughwhich the card or indicating means can be read. The frame of the compassmay have an aperture or slot therein extending under the bowl forreceiving an assembly including the compensating mechanism and a maskingplate for the front of the compass. The transparent panel or glassclosing the front aperture of the bowl may have a resilient metal sealring which may be soldered at one edge to the glass and soldered at itsother edge to the margins of the bowl aperture. The glass thus will beresiliently supported and will not require a sealing ring and pressureto be applied thereto. Furthermore, the glass may be disassembled bymerely heating the front of the bowl.

These and other objects, advantages and features of the invention willbecome apparent from the following description and drawings.

In the drawings:

Fig. 1 is a sectional elevation.

Fig. 2 is a front view reduced in size.

Fig. 3 is a fragmentary front view with a portion of the card brokenaway.

Fig. 4 is an enlarged fragmentary broken section of the pivot support.

Fig. 5 is a fragmentary top view of the card assembly.

Frame 10 may have a bowl or chamber 11, said chamber 11 having asuitable compass Huid therein. The frame and bowl may be made ofaluminum or other suitable non-magnetic material. Aperture 12 is at thefront of slot 13 in the frame for receiving sub-assembly 14, saidsub-assembly or carrier including a front masking plate 15 and thecompensator assembly 16A.

The compensator assembly may be of any suitable type. The oneillustrated includes two pairs of shafts located at right angles to eachother, 17, 17 being one pair and the other pair being back of adjustingshaft 16. These shafts have transverse pieces of magnetized material.The shafts can be adjusted, and thus the compensation, by turningadjusting screws under indentations 19B and 19C of cover plate 19D. Whenshaft 16 is turned by engagement ofslot .19, worm 18 will turnmeshedgears 18A and thus rotate shafts 17. Screw 19A holds cover 19D in place.

When it is desired to adjust or replace the compensating mechanism, itis possible to do so in the present invention by removing screws 20 anddrawing the carrier subassembly 14 forwardly and out of slot 13 in mainframe 10. Masking plate 15 is a part of the assembly.

A lighting arrangement is seen at 21, connection thereto being at 21A,such being described in detail in copending application Serial No.421,332, filed April 6', 1954. i

Bowl 11 has a front aperture 22 which can be closed by transparent panel23 in a novel manner, such panel being glass or other suitable material.The panel or glass 23 has a C shaped or equivalently arranged eXiblemetal ring; 24 which may1be joined by soldering at edge 25 with the`glass.Y Edge 26 can be joined'to the margins of the bowl by soldering soas to form a tluid tight joint therewith. It can be seen that themounting of the glass plate in the aperture does not require the usualgaskets and sealing mechanisms to hold it in place.

In assembling the parts, it is a simple matter to apply a soldering ironto the front of the frame 10 adjacent the aperture 22 so as to causesufficient heat to be applied to effect soldering of ring 24 with itsglass to the frame and thus close the front aperture of bowl 11.

In removing the glass, it is merely necessary to put the front of thecasing on a hot plate.

Filling plug 27 can be provided in the top of the bowl. Cover 28 may beof suitable material held in place as desired by screws or in any othermanner. Expansion capsules or bellows 29 communicate by means of passage30 with the interior of bowl 11, the capsules providing an expansionchamber for the uid in the bowl 11. Passageway 30 is formed and locatedso that liquid flowing into the bowl from the bellows will be directedupwardly and away from the oat assembly 31. Such will tend to preventundesirable eddies within the bowl.

A lubber line 32 is provided for receiving light through the port 33 inthe manner described in said copending application Serial No. 421,332.

The oat or card assembly 31 may comprise cup shaped card 34 which canhave figures or indicia pressed therein, said igures being suitably lledwith marking paint. By indenting the figures, the card is stilened.

The oat assembly can be carried on the doughnut or tore shaped oatchamber 35, said float chamber being made in two parts 36, 37 as shown.The two parts of the oat can be made of light metal and pressure weldedor bonded to withstand lluid pressure. The magnetic supporting element38 has a formed portion 39 to which the oat assembly 37 with attachedcard 34 is assembled. Adjustable pivo-t member 40 can have screw threadsthereon passing through nut 41, which is adjustable thereon, nut 42being provided for holding the magnet supporting member 39 and the iloatassembly in adjusted position relative to each other. The height of theassembly relative to support 43 can be adjusted and the oat assembly andcard can be rotated relative to the magnet assembly 38 so as to suitablyalign these parts relative to each other.

Magnets 44 are carried by the magnet carrying member 38. It is to benoted that by the construction involved herein the magnets arerelatively low in the bowl and that the center of gravity relative tothe support can be adjusted with ease'.

Pivot support 43 is arranged so as to hydraulically damp vibrationswhich might occur. This may be accomplished by providing a cylinder 45carrying the pivot Restricted i aperture 49 is l providedx at.y theLupper part. of=

cylinder 4S v sothat fluidl r`canow `in. and .out` offthe cylin-`deras-theparts reciprocate; Thus,l in case-ofivibration1 therewill `be adampinglmovement -fofthedloat assembly 31 relative to the frame. Conicalspring SDfisarranged to urge the cylinder4S'upwardlyrrelative-to'thepiston` 47, the spring'and yieldable support being .chosen so that thenaturalfrequency ofthe bearing assembly issuch that when subjected -tomovements withinl the vfrequency: range of the aircraft contact will' bemaintained between the parts.-

It shouldbeapparent vthat variationsmay be made in details f ofconstruction=without departing .from the spirit of the invention exceptas dened in the appended claim.

Iclaim:

Ina Huid compass, the combination including'a. fluid filled bowl, ysaidbowl havinga chamber with concave vertical walls, a magnetic card havinga centralhollow doughnut shaped oat in saidbowl supported on apivottherein, a transparent panel in one wall'of'said bowl for reading thecard, and an expansion chamber connected to saidbnwl through a passageon one. ofsaidyettical. .911.-

cave faces of said chamberv above said card, the outlet axis of saidpassage into said bowl being directed upwardly toward the roof of saidchamber and away from said card.

References Citedin thele of this patent UNITED STATES 'PATENTS 291,403Ritchie V K Y Jan. 1, 1884 1,256,442 Creagh-Osborne etal. Feb. 12, 19181,679,764 Colvin Aug. 7, 1928 1,925,863 Crocker Sept. 5, 1933 1,993,548Holmes Mar. 5, 1935 2,202,154 Kollsman. May 28, 1940 2,242,126 Holmes etal. May 13, 1941 2,280,726 Sperry Apr. 21, 1942 2,316,777 Fell Apr.20,1943 2,402,638 Krasnow et al; June 25, 1946 FOREIGN', PATENTS 679,074France Jan. 5, 1930 48,475 France Nov. 29, 1937 (1st addition toNo.r798,520)

